The Copper Labs

The Copper Labs

Purpose: What happens to copper metal as it goes through various chemical reactions?

Day 1 Starting the Copper Series

Background: Some substances react very fast. When a test tube full of hydrogen and oxygen is ignited, the reaction is very fast. Solids usually do not react as fast as gases. In this experiment, you investigate how the reaction of finely divided copper with oxygen in the air proceeds with time.

Procedure:

1.  Place a scoop of copper granules into a crucible.

2.  Mass the crucible and copper.

3.  Heat the crucible for 20 minutes. Stir gently for the first 2 minutes and occasionally there after. Watch for signs of change.

4.  Let the crucible and contents cool.

5.  Take the new mass of the crucible and contents.

6.  Break up the contents of the crucible with a scoopula and examine the pieces.

7.  Pour the contents of the crucible into a clean, dry test tube to be used the next day.

8.  Label the test tube with your name, lab station number, and class period. Place in the appropriate test tube rack.

Questions:

1.  Does a reaction take place during step 3?

2.  Did the mass change from step 2 to step 5? Explain any change.

3.  Was a substance added or subtracted from the copper? What was it?

4.  Predict what happens if you continue heating the crucible for an additional 10 minutes?

5.  In step 6, do you think all the copper has reacted? Estimate the percentage of copper that did not react.

6.  What type of chemical reaction is this? Write the equation, identify the reactants and products.

Day 2 Separating Copper Oxide

Background: If all the copper your started with in the first experiment reacted with oxygen, then the black solid present at the end would be a pure substance of copper oxide. If not all the copper reacted, then the black solid would be a mixture of copper and copper oxide. Today, we separate our solids to see if they completely reacted. Copper oxide dissolves easily in hydrochloric acid, yet copper does not.

Procedure:

1.  Place all of the black solid from your previous experiment in a test tube containing 5 mL of hydrochloric acid (HCl).

2.  Stir gently with a glass stirring rod for 5 minutes. CAUTION: Do not get any HCl on yourself or your clothes. If acid spills on your hands, wash them thoroughly with water. Let teacher know if any spills on the counter.

3.  Let the solid settle to the bottom. Slowly pour off (decant) the LIQUID BACK INTO your labeled test tube.

4.  Wash the remaining solid several times with water.

5.  DO NOT discard the acid solution. You will need it for the next experiment.

6.  Place your labeled test tube (same one from Day 1) in the appropriate test tube rack.

7.  Pour remaining solid in the proper container.

8.  Wash your lab station down and clean up.

Questions:

1.  What does the remaining solid look like after step 2?

2.  Was the remaining black solid from Day 1 a mixture? Explain your answer.

3.  After adding the acid, a chemical reaction took place. What indicators of a chemical reaction did you notice?

Day 3- Zinc and Copper

Background: When you heated a sample of finely divided copper, its mass increased. This indicated that something was being added to the copper. A new substance, copper oxide, was formed. You then dissolved the copper oxide in hydrochloric acid, and from the black substance you produced a dark solution. What happened to the copper in all these reactions? Did it disappear forever or is it still in the solution in some form? Putting a piece of zinc in the solution will provide you with the answer.

CAUTION: The reaction between zinc and hydrochloric acid will generate heat. Therefore, for safety reasons, clamp the test tube containing the solution in a beaker half filled with cold water.

Procedure:

1.  Make sure the test tube is secure on the clamp and the beaker has cold water. If it needs to be cooled, obtain either an ice cube or refill it using the teacher’s station sink.

2.  Put a piece of zinc in the solution you saved from the previous experiment.

3.  Gently stir the contents of the test tube until the reaction begins. Not the color of the solution as the reaction takes place.

4.  After the zinc has finished reacting, pour off (decant) the solution from the remaining solid and wash the solid several times with water to remove the acid.

5.  Remove the washed solution from the test tube and dry it by pressing it between layers of paper towel.

6.  While applying pressure, slide the scoopula across the dried solid.

Questions:

1.  What does the end solid look like? Try to identify it.

2.  What would happen if you heated the solid that you recovered in this experiment?

Name ______Hr. ______Date ______

Copper Labs

Day 1: Starting the Copper Series

Lab Data

Mass of crucible and copper before heating= ______

Mass of crucible and copper after heating = ______

Change in mass= ______

Questions

1.  Does a reaction take place during step 3? Explain your observations.

2.  Did the mass change from step 2 to step 5? Explain any change.

3.  Was a substance added or subtracted from the copper? What was it?

4.  Predict what happens if you continue heating the crucible for an additional 10 minutes?

5.  In step 6, do you think all the copper has reacted? Estimate the percentage of copper that did not react.

6.  What type of chemical reaction is this? Write the equation, identify the reactants and products.

Day 2- Separating Copper oxide

Questions:

1.  What does the remaining solid look like after step 2?

2.  Was the remaining black solid from Day 1 a mixture? Explain your answer.

3.  After adding the acid, a chemical reaction took place. What indicators of a chemical reaction did you notice?

4.  Write a chemical equation for this reaction using the symbols listed below.

CuO- copper oxide

CuCl2- copper chloride

HCl-hydrochloric acid

H2O- water

5.  What type of reaction is this?

Day 3- Zinc and Copper

Questions

1.  What does the solid look like at the beginning?

2.  What does the end solid look like? Try to identify it.

3.  What would happen if you heated the solid that you recovered in this experiment?

4.  Write a chemical equation using the symbols listed, for this chemical reaction.

Cu- Copper

CuCl2- copper chloride

Zn- zinc

ZnCl2- zinc chloride

5. What kind of chemical reaction is this?

CONCLUSION:

Write 1 paragraph explaining each day of this lab. Each paragraph should include a topic sentence, the type of reaction you observed, and an explanation of why you chose that reaction type using evidence from the lab. Use the space provided below.